Plate for serving hot meals thereon

ABSTRACT

The present invention concerns a plate ( 1 ) suited for directly dressing and serving meals directly thereon, which plate ( 1 ) comprises a heat storing material ( 14 ) allowing keeping the meal dressed thereon warm for an extended period of time in view of regular plates without heat storing material.

FIELD OF THE INVENTION

The present invention concerns a plate suited for directly dressing andserving meals directly thereon, which plate comprises a heat storingmaterial allowing keeping the meal dressed thereon warm for an extendedperiod of time in view of regular plates without heat storing material.

BACKGROUND TO THE INVENTION

When serving hot meals in restaurants, on events, during plane flightsand in other situations where the place of dressing a plate is distantfrom a place of serving the meal it is a challenge to keep the foodwarm.

WO 90/14783, U.S. Pat. No. 5,125,391, U.S. Pat. No. 4,304,106 forexample disclose trays for storing and transporting plates therein.These trays all include a heat storing material such as a phase changematerial that can store heat rapidly and release the heat more slowlyover an elapsed period of time.

A drawback of such trays is that these are not suited for serving fooddirectly thereon but are intended for storing one or more plates withfood thereon to enable serving food on these plates at a desiredtemperature during a relative long period of time. Moreover the use ofsuch trays is generally considered non-appealing for serving food.Another drawback is that with trays as described in at least U.S. '391and U.S. '106 the heat storing material is provided in a cavity definedby a top and bottom shell of the tray, whereby in case of damaging oneof these shells the heat storing material may leak out of the cavity,especially when at a elevated temperature (generally about 60° C.) whenthe heat storing material is in a fluid state. As such temperature iscommon in for example a dishwasher, dish washing a damaged trayaccording to U.S. '391 or U.S. '106 can seriously damage a dishwasherdue to leakage of the heat storing material (which when temperaturedrops again can solidify in the tubings).

Yet another disadvantage is that the heat storing material is notrestricted in its flow in the cavity when in a liquid state. As aconsequence, when slightly tilting a tray the liquid will flow to oneside and promote further tilting and hence instability when carrying apile of trays.

WO 03/079869 discloses a plate for direct contact with food servedthereon, comprising a slot in its lower surface for accommodating acartridge of heat storing material therein.

A drawback of such plate is that the plate and cartridge are twoseparate items that need to be assembled and disassembled for each usecycle, which is cumbersome and very impractical in restaurants or onlarge events where dishwashing the plates and re-use of the plates needsto be fast and effective.

Moreover in a plate according to WO '869 the heat storing material isvisible at the bottom of the plate and is considered potentiallyunappealing for people being served. It is clear from the above thatthere remains a need for an appealing, easy to use and handle, safe touse and efficient plate for serving food thereon and for remaining thisfood warm during an extended period of time in view of food served onnormal plates without specific heat storing material.

SUMMARY OF THE INVENTION

The present invention addresses the above identified need by providing aplate for direct contact with food served thereon, said platecomprising: (a) an upper part defining a well of the plate for receivingfood and an outer rim extending along at least part of the periphery ofthe well; (b) a base part fixed to the upper part thereby defining asealed cavity between the upper and base parts (c) an amount of latentheat storing material disposed in said sealed cavity wherein said heatstoring material is provided in a sealed flexible pouch.

Preferably, the heat storing material fills the pouch substantiallyentirely.

It is preferred that the cavity is situated under at least part of thesurface of the well of the plate and under at least part of the outerrim of the plate and that the volume of the cavity V(c) is larger thanthe volume occupied by the pouch thereby defining a free volume in thecavity, the free volume being situated under the outer rim of the plate.

The volume of the cavity V(c) and the volume of the heat storingmaterial in its expanded phase V(e) are preferably chosen such that theratio V(e)/V(c) is comprised between 0.6 and 0.9.

The heat storing material preferably is a phase change material (PCM)chosen from the group comprising: hydrated salts, organic compounds,solid to solid PCMs, eutectic solutions and/or admixtures thereof.

The pouch is preferably manufactured in a material comprisingpolypropylene, polyethylene, polyester such as polyethyleneterephthalate (PET) or polyethylene terephthalate glycol-modified(PET-G), polyamide and/or combinations thereof, whereby polyamide 66 ishighly preferred. In a particularly preferred embodiment, the pouch ismanufactured of a sandwich material comprising at least one layer ofpolypropylene and at least one layer of polyamide or polyester. In aspecific embodiment of the pouch according to the previous embodiment,said polypropylene layer is positioned internally with respect to thelayer comprising polyamide or polyester or a combination thereof, or iscovered by the layer comprising polyamide or polyester or a combinationthereof. In a further specific embodiment, the pouch is manufactured ofa sandwich material comprising polypropylene layer covered by apolyamide layer. In an alternative embodiment, the pouch is manufacturedof a sandwich material comprising polypropylene layer covered by apolyester layer, wherein said polyester is preferably selected from agroup comprising polyethylene terephthalate (PET) or polyethyleneterephthalate glycol-modified (PET-G).

The plate or at least the upper and or lower part thereof is preferablymanufactured in a material selected from the group comprising: ceramicmaterial such as glazed ceramics or porcelain.

According to a preferred embodiment a heat reflective layer is providedbetween the base part facing the cavity and the pouch.

Further a partitioning wall may be provided in said cavity and defininga compartment wherein the pouch is confined and another compartmentsubstantially corresponding to the free volume.

The plate according to the present invention preferably has a totalweight of 1 kg or less, preferably 0.8 kg or less.

The present invention also concerns a method of manufacturing a plate asidentified above, said method comprising the steps of: a) providing anupper part and a base part; b) providing a pouch filled with a heatstoring material with desired heat absorbing and releasing properties;c) accommodating the pouch on the intended top surface of the base partor the intended lower surface of the upper part and subsequently fixingthe upper part and base part to enclose the pouch in a cavity definedboth the upper and base part of the plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically represents a perspective cut-out view of a plateaccording to the present invention;

FIG. 2 represents a cross-section according to line II-II in FIG. 1;

FIG. 3 represents an alternative embodiment of a plate as depicted inFIG. 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 represents a plate 1 according to the present inventioncomprising an upper part 2 and a base part 3 with a sealed cavity 4defined in between both part 2 and 3. In this case the upper part 2comprises a generally planar disc-shaped well 5 and a slanting outer rim6 extending along the periphery of the well. The outer rim 6 comprises aflange 7 that extends from the outer periphery of the rim towards thebase part, thereby defining a void 8 between the outer rim and saidflange. At the free end of said flange a rim 9 is provided extendingtransversally in view of the well and away from said well. In thecircular circumference a circular slot 10 is provided.

The base part comprises a rim 11 along its periphery extending into thecavity 4 and defining a circular shoulder portion 12 able to cooperatewith the slot circular slot 10 of the upper part for (hermetically)sealing and fixing the base part to the upper part.

The base part 3 and upper part 3 can be fixed by welding (frictionwelding; laser welding; ultrasonic welding) or by gluing, depending onthe material wherein both parts are manufactured.

The upper part and base part can be manufactured from the same materialor from different materials chosen from the group comprising: porcelain,plastic, metal or admixtures thereof. Preferably both parts 2 and 3 aremanufactured in glazed ceramics such as porcelain, in which case it ispreferred to apply glue for fixing the upper part and base parttogether.

According to the invention a pouch 13 filled, preferably entirely filledwithout air entrapment, with a heat storing material, most preferably aso-called phase change material 14, is accommodated in said cavity 4.

The pouch 13 is preferably manufactured in a flexible and elasticpolymeric material such as polypropylene, polyamide or polyethylene,whereby polyamide 66 is preferred for the reason that it allows goodspreading of the PCM material without the sidewalls of the pouch toadhere to one another. The material wherein the pouch is manufacturedpreferably has a high tear resistance. In a preferred embodiment, thematerial of which the pouch is manufactured is a sandwich materialcomprising at least one layer of polypropylene and at least one layer ofpolyamide or polyester. In a particular embodiment, said sandwichmaterial comprises polypropylene layer that is positioned internallywith respect to the layer comprising polyamide or polyester or acombination thereof, or is covered by the layer comprising polyamide orpolyester or a combination thereof. In further embodiments, the pouch ismanufactured of a sandwich material comprising polypropylene layercovered by a polyamide layer or of a sandwich material comprisingpolypropylene layer covered by a polyester layer, wherein said polyesteris preferably selected from a group comprising polyethyleneterephthalate (PET) or polyethylene terephthalate glycol-modified(PET-G).

The PCM material as per the present invention is defined as a materialcapable of absorbing, storing, and releasing an amount of energy for along period of time. The latent heat or cold storage process can beachieved through a phase change, like for example from solid to solid,solid to liquid, solid to gas and liquid to gas, once the material hasbeen subjected to a certain temperature called melting temperature.

Moreover, this process can be repeatedly achieved by reaching themelting temperature of the phase change material. The PCM material 14may include for example: hydrated salts such as Na2 SO4, 10H2 O; Na2HPO4, 12H2 O; CaCl2, 6H2 O; [Na2 CO3 ]2, 10H2 O; Mg[NO3 ]2, 6H2 O;MgCl2, 6H2 O; MgSO4, 12 H2 O; sodium acetate trihydrate, glycols such aspolyethylene glycol, clathrates, hydroxides, Hydrophobic RT40 Powder,paraffin like octadecane, n-Paraffins, sugar alcohols or fatty acids;paraffin mixed with hydrophobic silica, non-paraffin organic compounds,such as lauric acid, napthalene, magnesium nitrate; acetimide; benzoicacid; strontium bromide; naphthalene; a mixture of urea and benzoicacid, a mixture of benzomide and benzoic acid, aluminum potassiumsulfate, ammonium nitrate, fatty acids, esters, silica gel or drypowder, eutectic solutions, ionic liquids or a combination thereof. Forassuring different storage and release of heat or cold properties thatwould be suitable for different types of applications, commerciallyavailable PCMs cover a phase change temperature range from −40° C. to+120° C., whereby for the present invention PCMs having a phase changetemperature between 50° C. and 65° C. are preferred.

An example of such PCM material is the n-paraffin based Rubitherm® RT 58commercialised by RubiTherm®. This PCM material has a phase changetemperature (melting temperature) ranging between 55-59° C. (typically58° C.); a heat storage capacity of 178 kJ/kg; a density (solid at 15°C.) of 0.88 kg/l; a liquid density (80° C.) of 0.77 kg/l; a volumeexpansion during phase change of 14%; a heat conductivity of 0.2 W/m*Kand a kinetic viscosity (at 90° C.) of 32.49 mm2/s.

The pouch, with the PCM in an expanded state occupies a volume V(e) thatis lower than the total volume V(c) of the cavity (including the void8), whereby the ratio V(e)/V(c) is preferably comprised in the rangebetween 0.6-0.9.

As represented in FIG. 2, the rim 11 provided on the base part 3preferably defines a partitioning wall in the cavity, thereby creating acentral compartment (below the well 5 of the plate) wherein the pouch isaccommodated and a free volume below the outer rim of the plate(substantially corresponding to the void 8).

According to a preferred embodiment, a heat reflective layer 15 or heatinsulating layer is provided between the pouch and the base part 3 ofthe plate 1.

FIG. 3 represents an alternative embodiment wherein the cavity isfurther partitioned in three or more, in this case four, compartments.One compartment under the outer rim of the plate free of PCM materialand three compartments under the well each accommodating a pouch withPCM material, whereby one pouch 13 a is filled with a

PCM material having a phase change temperature T; the second pouch 13 bis filled with a PCM having a phase change temperature T2 and the thirdpouch 13 c is filled with a PCM having a phase change temperature T3. Inthis case T1, T2 and T3 are preferably different and wherein thesetemperatures can range between 0° C. and 120° C., such as to createdifferent zones on the plate that are maintained at differenttemperatures during a certain period of time sufficient for dressing andserving food on said plate.

In this case the plate preferably comprises an indicator 16,accommodated in for example the outer rim 6 of the plate 1 and connectedto temperature sensors 17 designated to each of the PCM comprisingcompartments of the plate in order to provide a visual or otherindication of the temperature in the compartments corresponding tospecific sections of the well of the plate. Furthermore the plate maycomprise a number of separating walls 18 on the food receiving surfaceof the well 5, which walls 18 are arranged corresponding to the specificgeometry of the PCM pouches for different temperature zones on theplate.

Manufacturing a plate 1 according to the present invention comprises thesteps of: a) providing the upper part and the base part; b) providing apouch filled with a PCM material with a desired phase changetemperature; c) accommodating the pouch on the intended top surface ofthe base part or the intended lower surface of the upper part andsubsequently fixing the upper and base parts to enclose the pouch in thecavity defined both the upper and base part of the plate.

In use, the plate and specifically the PCM material accommodated thereinis heated to a desired temperature at or above its phase changetemperature and subsequently food can be dressed directly on the upperpart 2 of the plate 1, preferably in the well 5.

As the PCM material will release the heat stored therein over anextended period of time (generally up to 30 and even 60 minutes) thefood dressed and served on the plate will remain warm during thatextended period of time.

When serving the plate, a waiter can easily hold the plate at its outerrim as in this part no PCM material is present and as this part isfilled with a layer of air that acts as an insulator. In alternativeembodiments the free space in the cavity situated under the outer rim ofthe plate can be filled or partially filled with other insulatingmaterials such as a heat insulating foam.

By providing the PCM material directly under the surface of the platecontacting the food dressed and served thereon the total amount of PCMmaterial can be limited to for example between 60-390 cm3, preferablybetween 60-260 cm3, more preferably between 60-130 cm3 and mostpreferably between 90-130 cm3, thereby enabling limiting the totalweight of the plate (upper part+lower part+pouch+PCM material) to below2 kg, preferably below 1 kg even when both the upper plate and baseplate are manufactured in porcelain.

1. A plate for direct contact with food served thereon, said platecomprising: an upper part defining a well of the plate for receivingfood and an outer rim extending along at least part of the periphery ofthe well; a base part fixed to the upper part thereby defining a sealedcavity between the upper and base parts and an amount of latent heatstoring material disposed in said sealed cavity, wherein the heatstoring material is provided in a sealed flexible pouch.
 2. The plateaccording to claim 1, wherein said cavity is situated under at leastpart of the surface of the well of the plate and under at least part ofthe outer rim of the plate.
 3. The plate according to claim 2, whereinthe volume of the cavity V is larger than the volume occupied by thepouch, thereby defining a free volume in the cavity, the free volumebeing situated under the outer rim of the plate.
 4. The plate accordingto claim 1, wherein said heat storing material is a phase changematerial having an expanded state wherein the amount of PCM occupies avolume V and a non-expanded state wherein the amount of PCM occupies avolume V.
 5. The plate according to claim 4, wherein the ration ratio ofthe volume of the PCM in its expanded state to the volume of the cavityis between 0.6 and 0.9.
 6. The plate according to claim 4, wherein thePCM material is selected from the group comprising: hydrated salts,organic compounds, solid to solid PCMs, eutectic solutions and/oradmixtures thereof.
 7. The plate according to claim 1, wherein the upperpart and or base part are made of a ceramic material such as glazedceramics or porcelain.
 8. The plate according to claim 7, having a totalweight of 1 kg or less, preferably 0.8 kg or less.
 9. The plateaccording to claim 1, wherein the pouch is manufactured from acomposition comprising polypropylene, polyethylene, polyester such aspolyethylene terephthalate (PET) or polyethylene terephthalateglycol-modified (PET-G), polyamide and/or combinations thereof.
 10. Theplate according to claim 9, wherein the pouch is manufactured from acomposition comprising polyamide
 66. 11. The plate according to claim 9,wherein the pouch is manufactured of a sandwich material comprising atleast one layer of polypropylene and at least one layer of polyamide orpolyester.
 12. The plate according to claim 1, wherein a heat reflectivelayer is provided between the base part facing the cavity and the pouch.13. The plate according to claim 1, comprising a partitioning wallprovided in said cavity and defining a compartment wherein the pouch isconfined and another compartment substantially corresponding to the freevolume.
 14. A method of manufacturing a plate as identified in claim 1,said method comprising the steps of: providing an upper part and a basepart; providing a pouch filled with a heat storing material with desiredheat absorbing and releasing properties; accommodating the pouch on theintended top surface of the base part or the intended lower surface ofthe upper part, and subsequently fixing the upper part and base part toenclose the pouch in a cavity defined by both the upper and base part ofthe plate.